1. Field of the Invention
The present invention relates to a laminated ceramic capacitor using a dielectric ceramic.
2. Description of the Related Art
As described in JP 6-84692 A, in general, laminated ceramic capacitors include a ceramic body and external electrodes. The ceramic body has two principal surfaces opposed to each other, two side surfaces opposed to each other, and two end surfaces opposed to each other. The external electrodes are formed respectively on the two end surfaces of the ceramic body.
The ceramic body is a laminated body composed of: a plurality of ceramic layers for inner layers; a plurality of internal electrodes provided at the interfaces between the ceramic layers for inner layers; and a plurality of ceramic layers for outer layers, provided on the top and bottom so as to sandwich the plurality of ceramic layers for inner layers. The internal electrodes are electrically connected to the external electrodes.
The dielectric materials for use in the ceramic layers for inner layers are typically multiple oxides, many of which are perovskite-type compounds such as BaTiO3 and CaZrO3. These multiple oxides need to be prepared by synthesizing multiple expensive materials, in order to meet a wide variety of properties such as electrical properties and microstructure control. Therefore, the ceramic layers for inner layers are expensive in production cost.
On the other hand, the same dielectric material as the ceramic layers for inner layers is typically used for the ceramic layers for outer layers. Therefore, the ceramic layers for outer layers are also expensive in production cost.